fs/ceph/mds_client: fix memory leaks in ceph_mdsc_build_path()

fs/ceph/mds_client: fix memory leaks in ceph_mdsc_build_path()

Add __putname() calls to error code paths that did not free the "path"
pointer obtained by __getname().  If ownership of this pointer is not
passed to the caller via path_info.path, the function must free it
before returning.

Fixes: 3fd945a79e14 ("ceph: encode encrypted name in ceph_mdsc_build_path and dentry release")
Fixes: 550f7ca98ee0 ("ceph: give up on paths longer than PATH_MAX")
Cc: stable@vger.kernel.org
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>